An evaluation of automated blood collection mixers.

BACKGROUND AND OBJECTIVES We investigated the mixing capacity of two whole blood (WB) collection mixers. MATERIALS AND METHODS WB was simulated by using a 25% glycerol solution warmed to 35 degrees C. Citrate-phosphate-dextrose (CPD) anticoagulant of a collection system was stained with toluidine blue, and simulated WB was added at 30, 60 or 90 ml/min, respectively (n = 3 per flow speed). The optical density (OD) of 10-ml fractions was measured, and results are expressed as percentage of a well-mixed '100%-sample'. RESULTS CompoGuard showed adequate mixing at all three flow speeds (average ODs 96-103%). HemoLight showed good mixing at 60 and 90 ml/min (ODs from 97 to 101%). At 30 ml/min, mixing appeared suboptimal, but still conformed to our requirements with ODs from 96% to 104%. CONCLUSION Both mixers give sufficient mixing of whole blood with anticoagulant.